RF signal train generator and interferoceivers

ABSTRACT

New apparatus &lt;DEL-S DATE=&#34;20020226&#34; ID=&#34;DEL-S-00001&#34;&gt;comprise a&lt;DEL-E ID=&#34;DEL-S-00001&#34;&gt; &lt;INS-S DATE=&#34;20020226&#34; ID=&#34;INS-S-00001&#34;&gt;comprises an &lt;INS-E ID=&#34;INS-S-00001&#34;&gt;optical fiber based RF signal train generator for storing transient RF pulses and regenerating the identical replicas for analysis. The apparatus further &lt;DEL-S DATE=&#34;20020226&#34; ID=&#34;DEL-S-00002&#34;&gt;comprise&lt;DEL-E ID=&#34;DEL-S-00002&#34;&gt; &lt;INS-S DATE=&#34;20020226&#34; ID=&#34;INS-S-00002&#34;&gt;comprises an &lt;INS-E ID=&#34;INS-S-00002&#34;&gt;RF &lt;DEL-S DATE=&#34;20020226&#34; ID=&#34;DEL-S-00003&#34;&gt;receivers&lt;DEL-E ID=&#34;DEL-S-00003&#34;&gt; &lt;INS-S DATE=&#34;20020226&#34; ID=&#34;INS-S-00003&#34;&gt;receiver &lt;INS-E ID=&#34;INS-S-00003&#34;&gt;to process one stored pulse with a reference to &lt;DEL-S DATE=&#34;20020226&#34; ID=&#34;DEL-S-00004&#34;&gt;other&lt;DEL-E ID=&#34;DEL-S-00004&#34;&gt; &lt;INS-S DATE=&#34;20020226&#34; ID=&#34;INS-S-00004&#34;&gt;another &lt;INS-E ID=&#34;INS-S-00004&#34;&gt;stored pulse. The present invention drastically increases our abilities to investigate acoustical, electromagnetic, and optical transient phenomena.

This application is a continuation-in-part of application Ser. No.18,388 filed Feb. 17, 1993, which was refiled as Ser. No. 08/439,284 onMay 11, 1995 now U.S. Pat. No. 5,955,983, and a continuation-in-part ofSer. No. 877,419 filed May 1, 1992 now U.S. Pat. No. 5,294,930 and acontinuation-in-part of Ser. No. 787,085 filed Nov. 4, 1991 now U.S.Pat. No. 5,296,860.

TECHNICAL FIELD OF INVENTION

This invention relates to an apparatus which utilize utilizes an opticalfiber loop based RF signal train generator to store transient pulses andregenerate their identical replicas for analysis. The present inventiondrastically increases our abilities to investigate acoustical,electromagnetic, and optical transient phenomena.

BACKGROUND

Interferometer is a widely used instrument. The constituents ofinterferometers may vary, but they all comprise these essentialelements: a source, a splitter, two paths, and a detection apparatus.The source may generate acoustical, electromagnetic, and light wave,which is split into two paths by the splitter. The detection apparatuscompares waves from the two paths, and determine determines theirvariational differences. Interferometer is a powerful instrument, whichis capable of probing micro, meso, and macro systems. A system undertest may be the source, the splitter, or an external system insertedinto an interferometer path. We can infer the physical characteristicsof the system under test from the observed variational differences.

An interferometer with a continuous wave source requires both theinterferometer and system under test to be stable and stationary. Anyrandom and vibrational motion will blur the variational differences, andmask the physical characteristics of the system under test. Aninterferometer with a short-pulsed source will freeze a transientnatural event. However, with a conventional interferometer we are notable to decipher completely the variational difference created by asingle transient event. Multiple pulses and events are needed, thus theshort pulse and the transient event have to be exactly and repeatedlyreproduced. This may not be possible with all transient events.

Digitizing receiver is another widely used instrument. It comprises aradio frequency (RF) receiver and a digitizer. In a receiving process,the RF receiver first converts an RF signal to an intermediate frequency(IF) signal, and then to a video signal. A digitizer converts the analogvideo signal to a digital signal. The capability of a digitizer dependson its sampling rate. Digitizers with sampling rate of 200 MHz arecommercially available. Digitizers with sampling rate of 1 GHz have beenreported. Depending on the capability of a digitizer, the downconversion to a video signal may not be needed and a digitizer maydirectly digitize a an IF signal. A down conversion will filter awaymany intrinsic traits of a transient event. Most radar receivers have IFfrequency of 60 MHz. More sophisticated RF receivers have IF frequencyof 10 GHz to preserve the intrinsic traits of subnanosecond RF pulses.It is still impossible for a digitizing receiver to completely capturethe intrinsic traits of a single RF pulse with frequency of 10 GHz andpulse width of 1 GHz. Multiple pulses and events are again needed.

In light of the above, there is a need in the art for a new apparatuswhich are is capable of capturing the intrinsic traits of anddetermining the variational differences created by a random, chaotic,turbulent, or transient phenomenon. Furthermore it will reveal thephysical traits of a single transient event without instabilityblurring. An interferoceiver with RF signal train generator will fulfillthe needs to capture transient traits and to overcome the blurring. Thephysical principle for the new interferoceiver to capture an a transientevent is the same as that for optical fiber based radars with an RFsignal train generator.

THEORY OF INVENTION

The conventional method, which rests on the available technology. As thetechnology evolves, we are able to decipher a single transient eventcompletely. The technology is the optical fiber RF delay loop based RFsignal train generator. The information concerns the delay loop andgenerator can be found in the parent patent applications. With theirhelp, a radar is able to determine the range and Doppler shift of atarget with a single radar pulse. We will give a brief discussion hereon the RF signal train generation.

Let us assume the single input RF pulse to the loop has the form

A(t−t_(i)) Exp{+j ωt},   (1)

where ω is the circular frequency of the RF pulse with a pulse profile A(t-t_(i)) centered at the time t_(i). Experimentally we can not decipherthe intrinsic characteristics of a short RF pulse. It is the limitationimposed by the sampling rate and Nyquist theorem. RF pulses aretransient. Media were not available to record a transient RF: pulsefaithfully for the examination at a later time. Since the experimentalmeans did not exist for completely deciphering a short RF pulse, we hadto rely on the alternative alternate methods. These methods are onlyuseful to those short RF pulses which can be reproduced exactly by theirrespective sources. We then examine a portion of each reproduced pulse.The information from the reproduced pulses are is aggregated to completethe deciphering of a short RF pulse. A sample oscilloscope uses such amethod to decipher a short RF pulse.

Now the optical fiber RF delay loop provides an alternative alternatemethod. The delay loop causes the pulse delay of the input RF pulse. Thepulse train emerged from the optical fiber delay loop can be expressedas $\begin{matrix}{{\sum\limits_{i = 1}^{N}{{A\left( {t - t_{i}} \right)}{Exp}\left\{ {{+ j}\quad \omega \quad t} \right\}}},} & (2)\end{matrix}$

where N is the number of pulses in the train, τ the time delay of theloop, and t_(i)=i×τ denotes the time delay of a an RF pulse emerged fromthe storage loop after looping i times. The delay caused by an opticalfiber is a dynamical delay. RF pulse in the emerging train replicatesthe input RF pulse. By examining the copies of its replicas, a short RFpulse can be completely deciphered and repeatedly examined. It isimpossible with a conventional digitizing receiver or interferometer.

A reference pulse is required in deciphering an RF pulse. It plays tworoles. These are the triggering in a digitizing receiver and thereferencing in an interferometer. The triggering instructs the digitizerwhen to sample. The referencing provides an interferometer with a basisin evaluating what a transient phenomenon has affected the probingpulse. An additional optical fiber RF delay loop has to be introduced inyielding a reference pulse train. An RF signal train generator comprisestwo identical optical fiber RF delay loops, which will fulfill theneeds. We then examine each copy of the RF pulse replicas with the helpfrom a copy of the reference pulse replicas.

Pulsed signals may be acoustical, electromagnetic, and optical. Thesepulse signals in their respective receivers and interferometers will beeventually converted to the electromagnetic pulse signals. Hence, RFsignal train generators can be coupled with acoustical, electromagnetic,and optical signals to investigate their respective phenomena.

SUMMARY OF THE INVENTION

Embodiments of the present invention, which has a board functionalcapability, advantageously satisfy the above identified needs in theart. Embodiments of the present invention will provide aninterferoceiver which is versatile and sophisticated. Such aninterferoceiver will capture the intrinsic characteristics of atransient event without the blurring from its instability. Inparticular, embodiments of the present invention comprise optical fiberRF delay loops for storing short pulses, and reproducing their identicalreplicas.

In preferred embodiments of the present invention, the interferoceiversare equipped with an RF signal train generator, digitizing and intrapulse coherent processing subsystems. As a result, a new interferoceiverwill be able to freeze a transient event, and will have the functionalcapabilities of determining the statistical distribution, whichdescribes the instability of random, chaotic, turbulent, and transientphenomena. As those of ordinary skill in the art will readilyappreciate, in the light of intra pulse coherence, the instabilityblurring associated with multiple pulses will no longer be a problem,and external interferences from other sources will be drasticallyreduced.

In other embodiments of the present invention, the RF signal traingenerator, digitizing and intra pulse coherent processing subsystems aredirectly added to conventional digitizers and interferometers to upgradetheir functional capabilities as well as removing multiple pulserequirements for these instruments.

BRIEF DESCRIPTION OF THE DRAWING

A complete understanding of the present invention may be gained byconsidering the following detailed description in conjunction with theaccompanying drawings, in which:

FIG. 1 shows a block diagram of an optical fiber RF delay loop for usein fabricating embodiments of the present invention;

FIG. 1a shows a block diagram of a tapped optical fiber RF delay line ora set of optical fiber RF delay lines for use in fabricating embodimentsof the present invention;

FIG. 2 shows a block diagram of an RF signal train generator for use infabricating embodiments of the present invention;

FIG. 2a shows a block diagram of data flow from RF receiver to a mediumfor use in fabricating embodiments of the present invention;

FIG. 3 shows a block diagram of an interferoceiver for use infabricating embodiments of the present invention;

FIG. 4 shows a block diagram of an interferoceiver with a system undertest inserted into a path for use in fabricating embodiments of thepresent invention;

FIG. 5 shows a block diagram of an interferoceiver with a system undertest as the splitter for use in fabricating embodiments of the presentinvention;

FIG. 6 shows a block diagram of some sources for use in fabricatingembodiments of the present invention;

FIG. 7 shows a block diagram of some RF receiver functions for use infabricating embodiments of the present invention.

DETAILED DESCRIPTION

FIG. 1 shows a block diagram of an optical fiber RF delay loop 100 foruse in fabricating embodiments of the present invention. This is thesame optical fiber RF delay loop as in the parent patent applications ofoptical fiber based radars and optical RF stereo. As shown in FIG. 1,the optical RF signals through optical fiber 121 are applied as input toswitchable coupler 120. Switchable coupler 120 switches the optical RFsignals from optical fiber 121 into optical fiber loop 110. Isolator 140assures the optical RF signals in optical fiber loop circulating only inone direction. As the optical RF signals circulate the optical fiberloop 110, the strength of optical RF signals reduces. The reduction iscompensated by in-line optical amplifier (OA) 130 to keep the optical RFsignals circulating in the loop again and again until switchable coupler120 is closed. A portion of optical RF signals is switched from opticalfiber loop 110 to optical fiber 122 and the remainder of optical RFsignals will still circulate in optical fiber loop 110. The steps repeatagain and again. The closing of loop switch 150 will quench thecirculation of optical RF signals in optical fiber loop 110 beforeadmitting any new arrivals of optical RF signals from optical fiber 121.Switchable coupler 120, in-line optical amplifier 130, isolator 140 andloop switch 150 are well known to those of ordinary skill in the art.

FIG. 1a shows a block diagram of a tapped optical fiber RF delay line ora set of optical fiber RF delay lines for use in fabricating embodimentsof the present invention. The optical RF signals through optical fiber121 are applied as input to taps or splitter 1120. Taps or splitter 1120splits the optical RF signals and applies the split optical RF signalsas input to optical fiber RF delay lines 11111, 11112, . . . , 1111n.These delay lines have different lengths. Taps or combiner 1121 combinesthe optical RF signals from the optical fiber RF delay lines11111,11112, . . . , 1111n, and applies the combined optical RF signalsas input to optical fiber 122. Taps, splitter, and combiner are wellknown to those of ordinary skill in the art.

FIG. 2 shows a block diagram of an RF signal train generator 200 for usein fabricating embodiments of the present invention. This is the same RFsignal train generator as in the parent patent application of opticalfiber based radars. RF signal train generator 200 comprises twoidentical optical fiber RF delay loops according to the presentinvention. As shown in FIG. 2, two temporally aligned RF pulses 210 and220 are applied as inputs to their respective optical fiber delay loops230 and 240. So as not to loose clarity, optical fiber RF up and downconverters, and low noise amplifiers have not been depicted in FIG. 2.Loops 230 and 240 are identical and operated in a same manner thusrespectively producing two pulse trains 250 and 260.

As those of ordinary skill in the art will readily appreciate,embodiments of the present invention may not comprise an optical fiberRF storage subsystem as in comparison with optical fiber based radarsfor temporal alignment of two input pulses. The path length differenceof two paths from a source to the RF signal train generator usually issmall and can be simply adjusted through conventional RF means, whichare known to those of ordinary skill in the art. However, if the needarises, one may introduce an optical fiber RF storage subsystem as well.Embodiment of the optical fiber RF storage subsystem is described in theparent patent application of optical fiber based radars. Furthermore,one may double one of the optical fiber delay loop in the RF signaltrain generator as the optical fiber RF storage subsystem.

RF receiver (RFR) 30 uses direct digitizing and coherent receivingmethods to process pulse trains 250 and 260 from RF signal traingenerator 200. These methods are well known to those of ordinary skillin the art. The direct digitizing method uses one train as triggeringpulses to instruct the digitizer to sample the respective pulses of thesecond train. The triggering is systematically delayed in sampling thesequential pulses of the second train. The direct digitizing methodyields the intrinsic structure of the initial pulse, which generates thesecond pulse train. The coherent receiving method, based on the intrapulse coherence, uses the pulses of one train as reference to processvariational differences of their respective pulses of the second train.The mechanism to achieve intra pulse coherence was proposed in theparent patent application of optical fiber based bistatic radar. Thecoherent receiving method yields the relative amplitudes and phases, orthe relative frequency differences between RF pulses 210 and 220.Furthermore, RFR 30 will correlate pulse trains 250 and 260 to achieve aprecise determination of their variational differences. The manner inwhich RFR 30 processes RF pulse trains is well known to those ofordinary skill in the art. As those of ordinary skill in the art willreadily appreciate, RF signal train generator 200 of the presentinvention virtually mimics multiple pulses for RFR 30 to decipher theinformation contained in RF pulses 210 and 220.

As those of ordinary skill in the art will readily appreciate,embodiments other than the specific architecture shown in FIG. 2 may befabricated to provide the RF signal train generator. The optical fibermay vary its electrical length under external controls as a variabledelay line. The optical fiber RF delay loop may be replaced by a tappedoptical fiber RF delay line or by a set of optical fiber RF delay lines,as shown in FIG. 1a.

FIG. 2a shows a block diagram of data flow from RF receiver to a mediumfor use in fabricating embodiments of the present invention. Afterprocessing, RF receiver 30 produces a data stream 301. The data stream301 is then sent to medium 302.

FIG. 6 shows a block diagram of some sources for use in fabricatingembodiments of the present invention. Source ( 610 ) for aninterferoceiver may be acoustical ( 601 ), electromagnetic ( 602 ),mechanical ( 603 ), infrared ( 604 ), optical ( 605 ), nuclear ( 606 ),or other types.

FIG. 7 shows a block diagram of some RF receiver functions for use infabricating embodiments of the present invention. RF receiver ( 30 ) foran interferoceiver has one or many capabilities including those ofamplitude and phase measurements ( 31 ), relative amplitude and phasedetermination ( 32 ), frequency measurement ( 33 ), relative frequencydifference determination ( 34 ), correlation ( 35 ), and signal delaydetermination ( 36 ).

FIG. 3 shows a block diagram of an interferoceiver for use infabricating embodiments of the present invention. As shown in FIG. 3 theinterferoceiver is comprised of source 310, splitter 320, converters 323and 324, RF signal train generator 200, and RF receiver 30. Source 310,splitter 320, converters 323 and 324 are well known to those of ordinaryskill in the art.

During an operation, source 310 generates acoustical, electromagnetic,or optical signals for transit along path 311. Splitter 320 uses thesignals from path 311 as input and outputs two split signals.Furthermore, splitter 320 applies two split signals to two paths 321 and322 for transit to converters 323 and 324. Converters 323 and 324 thenuse the signals from paths 321 and 322 as inputs and convert themrespectively to optical RF signals. Converters 323 and 324 may simplypass through these signals, if conversions are not needed. Converters323 and 324 further apply optical RF signals respectively from paths 321and 322 to optical fiber paths 325 and 326 for transit to RF signaltrain generator 200. RF signal train generator 200 uses optical RFsignals as input and outputs two pulse trains with respective to opticalRF signals from paths 325 and 326. RF signal train generator 200 furtherapplies two pulse trains respectively to optical fiber paths 327 and 328for transit to RFR 30. RFR 30 uses pulse trains from optical fiber paths327 and 328 as inputs to process these two pulse trains.

RFR 30 may further comprise phase shifters and delay lines forprocessing transient signals from source 310. Furthermore, as is wellknown to those of ordinary skill in the art, RFR 30 will yield thespectrum of the signals, transient and intrinsic characteristics ofsource 310, and turbulence characteristics of the media surroundingsource 310.

As those of ordinary skill in the art will readily appreciate,embodiment of interferoceiver 300 will leads to investigation of manytransient and nonrepeatable signals in acoustics, electromagnetism, andoptics. Those signals in acoustics are the blasts, explosions, thunders,etc . . . . Those signals in electromagnetism are electromagnetic pulsesfrom lightning, violent electromagnetic discharge, electromagnetic pulseof opportunity, electromagnetic pulses emitted by nuclear blasts andcelestial objects, etc . . . . Those signals in optics are the lightsemitted by atoms and molecules in a turbulent media of burning,discharge, plasma, lightning, etc . . . . Furthermore, all the abovementioned signals are well know to those of ordinary skill in the art.

FIG. 4 shows a block diagram of an interferoceiver with a system undertest inserted into a path for use in fabricating embodiments of thepresent invention. As shown in FIG. 4, interferoceiver 400 is comprisedof source 410, splitter 420, converters 423 and 424, RF signal traingenerator 200, and RF receiver 30. Source 410, splitter 420, systemunder test 430, converters 423 and 424 are well known to those ofordinary skill in the art.

During an operation, source 410 generates acoustical, electromagnetic,or optical signals for transit along path 411. Splitter 420 uses thesignals from path 411 as input and outputs two split signals.Furthermore, splitter 420 applies two split signals to two paths 421 and422 for transit to converters 423 and 325. Signal of path 422 transitsthrough system under test 430. Intrinsic charateristics of system undertest 430 is random, chaotic, turbulent, or transient. As those ofordinary skill in the art will readily appreciate that signal of path422 will interact with system under test and be tainted with theintrinsic characteristics of system under test 430 after the transit.Then converters 423 and 424 use the signals from paths 421 and 422 asinputs and convert them respectively to optical RF signals. Converters423 and 424 may simply pass through these signals, if conversions arenot needed. Converters 423 and 424 further apply optical RF signalsrespectively from paths 421 and 422 to optical fiber paths 425 and 426for transit to RF signal train generator 200. RF signal train generator200 uses optical RF signals as input and outputs two pulse trains withrespect to optical RF signals from paths 425 and 426. RF signal traingenerator 200 further applies two pulse trains respectively to opticalfiber paths 427 and 428 for transit to RFR 30. RFR 30 uses pulse trainsfrom optical fiber paths 427 and 428 as inputs to process signal trainfrom path 428 by using signal train from path 427 as a reference. As iswell known to those of ordinary skill in the art, the reference signalsfrom splitter 420 through path 421, converter 423, path 425, RF signaltrain generator 200, path 427 to RFR 30 are protected from externalcontamination and interference.

As those of ordinary skill in the art will readily appreciate,embodiment of interferoceiver 400 is well suited for investigatingrandom, chaotic, turbulent, or transient features of emitting source 410and system under test 430. The observed intrinsic traits and variationaldifferences contain information on both emitting source 410 and systemunder test 430. With a known and pulsed source 410, the processing ofsignal train from fiber optical path 428 by RFR 30 yields the intrinsiccharacteristics of the random, chaotic, turbulent, or transient traitswithin system under test 430. As those of ordinary skill in the art willfurther appreciate, a coincident circuit may be needed to coordinate thesource pulse with a transient event from system under test 430.Furthermore, RFR 30 will separate stable traits of system under test 430from its random, chaotic, turbulent, or transient features. The methodof separation is well known to those of ordinary skill in the art.

As those of ordinary skill in the art will readily appreciate,embodiment of interferoceiver 400 with a pulsed ultrasonic source 410will lead to diffraction tomography for unstable systems. An unstablemotion leads to Doppler shift disturbances in diffraction fields andtomographic image blurring. Embodiment of interferoceiver 400 willfurther lead to ultrasonic imaging of unstable objects and of fetus. Asit is well known to those of ordinary skill in the art, RFR 30 throughFourier transformation and moving center correction will remove Dopplershift disturbances and sharp ultrasonic images of these systems.

As those of ordinary skill in the art will appreciate, embodiment ofinterferoceiver 400 with a pulsed electromagnetic source 410 will usesolid means of coaxial cables and wave guides to transit itselectromagnetic signals. For example, a single pulse from the pulsedelectromagnetic source 410 will lead to the determination of locationand speed for a fly in a transverse electromagnetic cell. As is wellknown to those of ordinary skill in the art, a conventional methods willonly able to determine the location of a fly at rest from a singleelectromagnetic pulse.

As those of ordinary skill in the art will readily appreciate,embodiment of interferoceiver 400 may use a an electromagnetic pulsefrom lightning as a source and cloud layers as system under test 430.RFR then will provide a detailed information concerning the structuresof these layers.

As those of ordinary skill in the art will appreciate, embodiment ofinterferoceiver 400 with a continuous wave (CW) laser source 410 and aan electromagnetic pulse sensor as system under test 430 will lead tothe capture of a single electromagnetic event. Furthermore, RFR 30 willprovide a detailed information concerning transient traits andelectromagnetic spectrum of the event.

As those of ordinary skill in the art will further appreciate,embodiment of interferoceiver 400 with a pulsed laser source 410 willlead to light scatterings by atoms, molecules, microorganisms, mediumfluctuations, plasmas, and particles suspended in chaotic media, andmany others. As is well known to those of ordinary skill in the art, thescattered lights are affected by the initial positions and velocities ofmicro objects and statistical properties of media. As is well known tothose of ordinary skill in the art, motion of micro objects andturbulence of media will lead to Doppler frequency shifts in scatteredlights. As those of ordinary skill in the art will appreciate, RFR 30through Fourier transformation will reveal the Doppler spectraassociated with the motion and turbulence, and their statisticaldistributions. As those of ordinary skill in the art will appreciate,embodiment of interferoceiver 400 will provide a much better tool thanconventional methods in revealing intrinsic characteristics of atoms,molecules, microorganisms, medium fluctuations, plasmas, and particlessuspended in chaotic media, and many others.

As those of ordinary skill in the art readily appreciate, embodiment ofinterferoceiver 400 with a pulsed laser source 410 will lead to lidarsand laser velocimeters. Conventional lidars, which are based on pulsedlasers, only measure the ranges of reflecting objects. Conventionallaser velocimeters, which are based on CW lasers, only measure theDoppler shifts from seeded particles. Lidars and laser velocimeters ofthe present invention, with a help of optical fiber RF storagesubsystems, will have both the ranging and Doppler capabilities. Asthose of ordinary skill in the art will further appreciate, thedistinction between lidars and laser velocimeters disappears in theteaching of the present invention. With a subnanosecond pulse source, wewill be able to locate constituents in a large reflecting assembly andmeasure their individual Doppler shift frequencies. As those of ordinaryskill in the art will readily appreciate, the teachings from the parentpatent applications of optical fiber based bistatic radar and optical RFstereo will lead to the embodiments for fabricating optical fiber basedbistatic lidar and optical light stereo.

As those of ordinary skill in the art will further appreciate, theincident and scattered laser pulses may be unsuitable for direct feedingto optical fibers. A second laser can be deployed to down convert theincident and scattered laser pulses to RF signals, then with the help ofoptical fiber RF converters to up convert the RF signals to optical RFsignals for transit through optical fibers to RF signal train generator.The processes of down and up conversions of laser pulses are well knownto those of ordinary skill in the art.

FIG. 5 shows a block diagram of an interferoceiver with a system undertest as the splitter for use in fabricating embodiments of the presentinvention. As shown in FIG. 5 interferoceiver 500 is comprised of source510, system under test 530, converters 523 and 524, RF signal traingenerator 200, and RF receiver 30. Source 510, converters 523 and 524are well known to those of ordinary skill in the art.

During an operation, source 510 generates acoustical, electromagnetic,or optical signals for transit along path 511. System under test 530uses the signals from path 511 as input, interacts with the signals, andoutputs two split signals. Furthermore, system under test 530 appliestwo split signals to two paths 521 and 522 for transit to converters 523and 524. Then converters 523 and 524 use the signals from paths 521 and522 as inputs and convert them respectively to optical RF signals.Converters 523 and 524 may simply pass through these signals, ifconversions are not needed. Converters 523 and 524 further apply opticalRF signals respectively from paths 521 and 522 to optical fiber paths525 and 526 for transit to RF signal train generator 200. RF signaltrain generator 200 uses optical RF signals as input and outputs twopulse trains with respective to optical RF signals from paths 525 and526. RF signal train generator 200 further applies two pulse trainsrespectively to optical fiber paths 527 and 528 for transit to RFR 30.RFR 30 uses pulse trains from optical fiber paths 527 and 528 as inputsto process signal train from one path by using signal train from theother path as reference.

As those of ordinary skill in the art will appreciate, for example,embodiment of interferoceiver 500 with a pulsed laser source 510 willlead to the correlation of scattered lights in a light scatteringprocess. The correlation yields the Doppler shift difference between twoscattered lights. The mechanism of Doppler shift differencedetermination was proposed in the parent patent application of opticalRF stereo. RFR 30 through Fourier transformation will reveal the spectraof the Doppler shift difference associated with the motion of microobjects and turbulence of media, and their statistical distributions.

ADVANTAGES AND OBJECTIVES

Embodiments of the present invention will provide advanced means toupgrade conventional digitizing receivers and interferometers than thosefurnished by the prior art. As those of ordinary skill in the art willfurther appreciate, embodiments of the present invention provide addedupgrades to the existing digitizing receivers and interferometerswithout modification, which in turn will be more cost effective and willnot interrupt their normal operation.

Embodiments of the present invention will enhance the functionaldiversities of conventional digitizing receivers and interferometers. Inaddition, the use of RF signal train generators makes it possible fordigitizing receivers and interferometers to completely decipher a singletransient event without instability blurring. Furthermore, embodimentsof the present invention enable digitizing receivers and interferometersto determine intrinsic traits and Doppler spectrum of a single RF pulse.

Embodiments of the present invention will be able to reveal many hiddenmechanisms governing many statistical phenomena. For instance, Dopplerspectra of a chaotic medium and a turbulent flow could not be directlyobserved. Statistical properties of the Doppler spectra now can besystematically investigated. As those of ordinary skill in the art willappreciate, embodiments of the present invention will lead to betterunderstandings of the chaotic media and turbulent flows.

As those of ordinary skill in the art will readily appreciate, averagingwith respect to multiple pulses will smear many critical informationconcerning the system under test. Embodiments of the present inventionuse a single pulse rather than multiple repetitive pulses. Theembodiment will make digitizing receivers and interferometers moreversatile and sophisticated in exposing many critical information. Asthose of ordinary skill in the art will still further appreciate,embodiments of the present invention will lead to better understandingsof random, chaotic, turbulent, or transient phenomena.

Embodiments of the present invention will be able to sharpen ultrasonicimages. Furthermore, embodiments of the present invention will be ableto separate the images of stationary constituents from that of movingconstituents. As those of ordinary skill in the art will equallyappreciate, optical fiber based radars will also sharpen syntheticaperture radar (SAR) images, and separate SAR images of stationaryconstituents from that of moving constituents.

Embodiments of the present invention will be able to reveal intrinsictraits of an active system. Intrinsic traits of an active system is areinherited, like imperfection in a diamond. As those of ordinary skill inthe art will equally appreciate, optical fiber based radars and passiveRF systems will provide excellent means in revealing the unintendedmodulation on pulse by active and passive objects.

Embodiments of the present invention will be advantageous to discloseinternal constituents of a system and to reveal their characteristics.As those of ordinary skill in the art will equally appreciate, opticalfiber based radars and passive RF system systems possess excellent meansin suppression of clutter returns and of multiple path interferences.

Embodiments of the present invention, as shown in FIG. 2a, will lead tomore effective means in deciphering a transient event than a fastdigitizer under development or a group of parallel digitizers. A fastdigitizer creates a massive data stream in a very short time interval.It is difficult for a medium to receive such a data stream.

Embodiments of the present invention will be advantageous in destructivetestings, for example, automobile collision tests. Transient signalsfrom various sensors will be thoroughly analyzed by interferoceivers.Embodiments of the present invention will provide better understandingsas well as reducing the costs in destructive tests.

Quantum mechanics is a mechanics of coherent. Many interesting coherentphenomena implicated by Einstein, Podolsky, and Rosen paradox are stillwaiting for us to discover. Embodiments of the present invention willprovide us new tools for us to discover these interesting phenomena.

SUMMARY, RAMIFICATIONS, AND SCOPE

Those skilled in the art readily recognize that embodiments of thepresent invention may be made without departing from its teachings. Forexample, the interferoceivers may have many designs as well as differentvariations. The source of an interferoceiver may play the role of asplitter as well. Two signals at different angle perspectives from asource are sent directly to the RF signal train generator. Aninterferoceiver may compare two sequential events from a source with thehelp from an optical fiber RF storage subsystem to temporally alignthese two events. Such a comparison leads to inter pulse coherence. Themechanism to achieve inter pulse coherence was proposed in the parentpatent application of optical fiber based radars. Thus the scope of theinvention should be determined by appended claims and their legalequivalent, rather by the examples presented here.

What is claimed is:
 1. An interferoceiver comprising: an input systemfor receiving one or more RF signals from a source and for applying theone or more RF signals to an RF signal train generator; wherein the RFsignal train generator comprises: means, responsive to the input, forstoring the one or more RF signals; means for regenerating replicas ofthe one or more stored RF signals; means for pairing the regeneratedreplicas; and means for outputting the paired replicas.
 2. Theinterferoceiver of claim 1 further comprising an RF receiver; whereinthe RF receiver comprises means for receiving the replicas of the RFsignals; and means for processing the replicas with a reference to theirpairs.
 3. The interferoceiver of claim 2 wherein said source comprisesmeans for generating an acoustical signal and for splitting thegenerated acoustical signal in parts; wherein the interferoceiverfurther comprises means for sending one of parts to the RF signal traingenerator; wherein the interferoceiver further comprises a system undertest, and means for sending other parts through the system under test tothe RF signal train generator; wherein the RF signal train generatorfurther comprises means for convening acoustical signals to RF signals.4. The interferoceiver of claim 2 wherein said source comprises meansfor generating an acoustical signal; wherein the interferoceiver furthercomprises a system under test, and means for sending the acousticalsignal to the system under test; wherein the system under test comprisesmeans for splitting the acoustical signal into parts, and for sendingsplit parts to the RF signal train generator; wherein the RF signaltrain generator further comprises means for converting acousticalsignals to RF signals.
 5. The apparatus of claim 2 wherein said sourcecomprises means for generating an RF signal and for splitting thegenerated RF signal in parts; wherein the interferoceiver furthercomprises means for sending one of parts to the RF signal traingenerator; wherein the interferoceiver further comprises a system undertest, and means for sending other parts through the system under test tothe RF signal train generator.
 6. The interferoceiver of claim 2 whereinsaid source comprises means for generating an RF signal; wherein theinterferoceiver further comprises a system under test, and means forsending the RF signal to the system under test; wherein the system undertest comprises means for splitting the RF signal into parts, and forsending split pans to the RF signal train generator.
 7. Theinterferoceiver of claim 2 wherein said source comprises means forgenerating an optical signal and for splitting the generated opticalsignal in parts; wherein the interferoceiver further comprises means forsending one of parts to the RF signal train generator; wherein theinterferoceiver further comprises a system under test, and means forsending other parts through the system under test to the RF signal traingenerator; wherein the RF signal train generator further comprises meansfor converting optical signals to RF signals.
 8. The interferoceiver ofclaim 2 wherein said source comprises means for generating an opticalsignal; wherein the interferoceiver further comprises a system undertest, and means for sending the optical signal to the system under test;wherein the system under test comprises means for splitting the opticalsignal into parts, and for sending split parts to the RF signal traingenerator; wherein the RF signal train generator further comprises meansfor converting optical signals to RF signals.
 9. A method for operatingan interferoceiver comprising steps of: (a) storing one or more RFsignals from a source in an RF signal train generator; (b) regeneratingreplicas of the one or more stored RF signals from the RF signal traingenerator; and (c) pairing the regenerated replicas.
 10. The method ofclaim 9 further comprising steps of: (d) processing the replicas in areference to their pairs.
 11. The method of claim 10 further comprisingsteps of: (e) generating an acoustical signal from the source; (f)splitting the acoustical signal into parts; (g) sending one of part tothe RF signal train generator and send other parts through a systemunder test to the RF signal train generator; and (h) convertingacoustical signals to RF signals.
 12. The method of claim 10 furthercomprising steps of: (e) generating an acoustical signal from thesource; (f) sending the acoustical signal to a system under test; (g)splitting the acoustical signal by the system under test and sending thesplit acoustical signals to the RF signal train generator; and (h)convening acoustical signals to RF signals.
 13. The method of claim 10further comprising steps of: (e) generating an RF signal from thesource; (f) splitting the RF signal into pans; and (g) sending one ofpart to the RF signal train generator and send other parts through asystem under test to the RF signal train generator.
 14. The method ofclaim 10 further comprising steps of: (e) generating an RF signal fromthe source; (f) sending the RF signal to a system under test; and (g)splitting the RF signal by the system under test and sending the splitRF signals to the RF signal train generator.
 15. The method of claim 10further comprising steps of: (e) generating an optical signal from thesource; (f) splitting the optical signal into parts; (g) sending one ofparts to the RF signal train generator and send other parts through asystem under test to the RF signal train generator; and (h) convertingoptical signals to RF signals.
 16. The method of claim 10 furthercomprising steps of: (e) generating an optical signal from the source;(f) sending the optical signal to a system under test; (g) splitting theoptical signal by the system under test and sending the split acousticalsignals to the RF signal train generator; and (h) converting opticalsignals to RF signals.
 17. An apparatus for investigating transientphenomena comprising: an input system for receiving an RF pulse from asource and for applying the RF pulse to an RF signal train generator;wherein the RF Signal train generator comprises: means, responsive tothe input, for storing the RF pulse; means for regenerating a train ofreplicas from the stored RF pulse; and means for sampling regeneratedreplicas in the train with different delays.
 18. The apparatus of claim17 wherein said source is an optical, infrared electromagnetic,mechanical or acoustical source.
 19. The apparatus of claim 17 whereinsaid RF signal train generator further comprises: means for receiving asecond pulse from the source and for generating the replicas of thesecond pulse; wherein the apparatus further comprises means forprocessing the replicas of the first pulse with a reference to thereplicas of the second pulse.
 20. The apparatus of claim 17 furthercomprises means for processing the replicas with an RF receiver.
 21. Aninterferoceiver comprising: an input system which receives one or moresignals and outputs RF signals; an RF signal train generator whichreceives the RF signals from the input system and outputs multiplepaired replicas of the RF signals.
 22. The interferoceiver of claim 21further comprising an RF receiver, which pairwise analyzes the pairedreplicas of the RF signals.
 23. The interferoceiver of claim 22 furthercomprising a source, which emits the one or more signals.
 24. Theinterferoceiver of claim 22 further comprising a source; wherein thesource emits one or more signals; wherein a splitter splits the one ormore signals into a first group of signals and a second group ofsignals; wherein the second group of signals transits to, and interactswith, a system; and wherein the input system is adapted to receive thefirst group of signals and the interacted second group of signals. 25.The interferoceiver of claim 22 further comprising a source; wherein thesource emits one or more signals which interact with a system; andwherein the input system is adapted to receive the interacted one ormore signals.
 26. The interferoceiver of claim 21; wherein the inputsystem comprises a splitter which splits the one or more signals. 27.The interferoceiver of claim 21; wherein the RF signal train generatorcomprises a pairing apparatus which pairs the generated replicas. 28.The interferoceiver of claim 21; wherein the RF signal train generatorcomprises an optical store which stores the RF signals as optical RFsignals.
 29. The interferoceiver of claim 28; wherein the RF signaltrain generator comprises an extractor which generates replicas of theoptical RF signals stored in the optical store.
 30. The interferoceiverof claim 29; wherein the optical store and the extractor are configuredso that the replicas generated by the extractor are paired.
 31. Theinterferoceiver of claim 28; wherein the optical store comprises one ormore optical RF delay loops, or comprises one delay lines.
 32. Theinterferoceiver of claim 22; wherein the RF receiver comprises adigitizer which analyzes the paired replicas of the RF signals by usingone of the paired replicas as triggering pulses to sample another one ofthe paired replicas.
 33. The interferoceiver of claim 32; wherein thedigitizer further comprises a delay apparatus which systematicallydelays the triggering pulses.
 34. The interferoceiver of claim 22;wherein the RF receiver comprises a coherent receiver which analyzes thepaired replicas of the RF signals by using one of the paired replicas asa reference to produce relative amplitudes and phases or relativefrequency differences between the RF signals.
 35. The interferoceiver ofclaim 21; wherein the input system is adapted to receive at least one ofoptical, infrared, acoustical, electromagnetic, mechanical, or nuclearsignals.
 36. The apparatus of claim 21; wherein the input system isadapted to output optical RF signals, and the RF signal train generatoris adapted to receive optical RF signals.
 37. A method for investigatingone or more signals comprising steps of: receiving the one or moresignals and outputting RF signals; receiving the RF signals by an RFsignal train generator; and outputting multiple paired replicas of theRF signals.
 38. The method of claim 37 further comprising a step of:pairwise analyzing the paired replicas.
 39. The method of claim 38further comprising a step of: emitting the one or more signals from asource.
 40. The method of claim 38 further comprising steps of:splitting the one or more signals into a first group of signals and asecond group of signals; interacting the second group with a system; andwherein the step of receiving comprises steps of receiving the firstgroup of signals and the interacted second group of signals.
 41. Themethod of claim 38 further comprising a step of: interacting the one ormore signals with a system; and wherein the step of receiving comprisesa step of receiving the interacted one or more signals.
 42. An apparatusfor investigating one or more signals comprising: an input system whichreceives the one or more signals and outputs RF signals; an RF signaltrain generator which receives the RF signals from the input system andregenerates a train of replicas; and a receiver which samples theregenerated replicas in the train with different delays.
 43. Theapparatus of claim 42; wherein the receiver further comprises acorrelator.
 44. The apparatus of claim 42; wherein the receiver isadapted to output a data stream, and to send the data stream to amedium.
 45. The apparatus of claim 42; wherein the input system isadapted to output optical RF signals, and the RF signal train generatoris adapted to receive optical RF signals.
 46. A method for investigatingone or more signals comprising steps of: receiving the one or moresignals; outputting one or more RF signals and regenerating a train ofreplicas of the RF signals; and sampling the regenerated replicas in thetrain with different delays.
 47. The method of claim 46 furthercomprising steps of: producing a data stream; and sending the datasystem to a medium.
 48. The method of claim 46 further comprising a stepof storing the one or more signals as one or more optical RF signals.